I attached a schematic of digital input selector. The schematic looks very interesting to me. I sent it to Mr. Jan Dupont some time ago, but it seems that he don't like digital inputs very much. For me it is interestin to know what do you think about digital inputs in common case. On the schemata is note, that it works. Did not made it by myself.

Looks very interesting, but im worried quality of that selector chip. Maybe it is better to use relays? And how about processor? I assume that processor goes to sleep (=clock frequency stopped) when user isnt do anything. Other way, there would huge disturbances in audio signal from processor.
- Mika